On 7/3/2024 7:09 PM, Jim Anderson wrote:
He also has an html page with the source code broken down and annotated 
(http://archives.oldskool.org/pub/drivers/Tandy/nemesis.lonestar.org/computers/tandy/software/apps/model100/period/per17m.html)
 which explains how the program works and goes into some detail on the 
struggles he had getting good consistent data on some of the elements to put in 
the program... (this is probably one of the printouts seen on the display table 
at the exhibition)

It is, and I found it entertaining:

"For crystal structure, I ran into a similar problems, and began to
wonder how anything can get done in area of Chemistry if the scientists
can't agree on the crystal shape of even a stable, common and
well-understood element like Oxygen. Three references offered three
different crystal structures for Oxygen (cubic, hexagonal and diamond),
and failed to all agree for almost a quarter of all the elements that
have known crystals. The CRC handbook would have been used as the final
authority, but they frequently failed to provide crystal information on
the simple elements in their tables, even though they listed freezing
points for the elements in question. For example, CRC did not list a
crystal structure for Mercury (Hg) and other sources did, but CRC did
list a crystal structure for Mercury chromate (HgCrO4) and numerous
other Mercury compounds, all of which was useless here.

Therefore, the crystal shape used is that which was stated in the 1980
edition of a Sargent-Welch periodic table I got back in 1982. The
elements discovered since then don't last long enough or the researchers
don't have enough of the atoms of that element in one place at the same
time for anybody to actually know what their crystal shape is, so using
this older reference wasn't a big problem.

I would accept corrections, but there seems little point since so many
respected publishers have so many discrepancies over what should be
universal constants. The lack of agreement means that having a
non-chemist trying to verify a submitted correction would be impractical."

Thanks for figuring this out.  I'll try to let someone know about the issue.


Jim

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